A hitherto widely known electronic device is equipped with an indicator that displays a status of the electronic device (e.g., activation/deactivation of the power) to a user by means of a lighting condition. Many of the indicators are equipped with a lightguide lens that guides light from a light source to the outside. The light guide lens is usually fitted into an insert hole opened in a design panel.
If the thus-attached light guide lens remains simply inserted into the insert hole, the lens will often detach itself from the insert hole. According to JP 2008-152844 A, after a light guide lens has been inserted into an insert hole, the light guide lens is welded to a design panel in order to prevent detachment of the lens from the insert hole. More specifically, according to JP 2008-152844 A, attachment holes into which bosses projecting out of a back surface of the design panel are to be inserted are formed in corner portions of the light guide lens (portions that do not act as a lens). Leading ends of the bosses projecting out of the attachment holes are melted by means of a soldering iron, thereby attaching the light guide lens to the design panel.
A technique disclosed in JP 2004-111568 A includes press-fitting a light guide lens made of a soft optical transparent element into an insert hole of a design panel, to thus secure a circumferential side surface of the light guide lens to an inner peripheral wall surface of the insert hole through pressure welding.
According to the technique for welding the light guide lens, such as that described in connection with JP 2008-152844 A, detachment of the light guide lens is prevented without fail. However, the technique requires a welding facility and encounters a problem of the inability to easily attach the light guide lens. Further, since a once-welded light guide lens cannot be removed, difficulty is encountered in disassembling and recycling the light guide lens.
According to the technique described in connection with JP 2004-111568 A, a light guide lens made of a soft light transparent material is used, and hence the lens can also be attached and detached with relative ease. However, since a special material, like a soft light transparent material, is utilized, there has been a problem of a tendency toward higher component costs.